A holographic recording medium on which data are recorded holographically has been already invented.
This holographic recording medium is a photosensitive recording medium which has holographic recording layers each made of photosensitive material provided on a substrate in a shape of a disc. Data are multilayeredly recorded on the holographic recording medium as interference fringes of laser light, so that the holographic recording medium can obtain a larger data recording capacity than that of a DVD which is a recording medium heretofore widespread. Exposure of the holographic recording layers to light or deposition of dust on the holographic recording layers exerts a bad influence on the performance of the holographic recording medium. For this reason, the holographic recording medium has been dealt with in the condition that the holographic recording medium is contained in a cartridge having a light-shielding function and dustproof function, and the cartridge of this type provided with a cartridge body, a shutter member, and a shutter cover has been known (JP-A-2003-317422 (corresponding to US 2003/0198177 A1)).